When an eject request is sent to an ejected ACPI device, the following
panic occurs:
ACPI: \_SB_.SCK3.CPU3: ACPI_NOTIFY_EJECT_REQUEST event
BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
IP: [<ffffffff813a7cfe>] acpi_device_hotplug+0x10b/0x33b
:
Call Trace:
[<ffffffff813a24da>] acpi_hotplug_work_fn+0x1c/0x27
[<ffffffff8109cbe5>] process_one_work+0x175/0x430
[<ffffffff8109d7db>] worker_thread+0x11b/0x3a0
This is becase device->handler is NULL in acpi_device_hotplug().
This case was used to fail in acpi_hotplug_notify_cb() as the target
had no acpi_deivce. However, acpi_device now exists after ejection.
Added a check to verify if acpi_device->handler is valid for an
eject request in acpi_hotplug_notify_cb(). Note that handler passed
from an argument is still valid while acpi_device->handler is NULL.
Fixes: 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
8fcfb99c8e